For the defense, it is the difference in staying with your assignment. Our major issue last year is that players were either reverting to what they knew from the old system, or saying, "f*** it, we need the puck back." and going out of their way to try and gain possession again, which had led to a lot of very bad scoring chances against. Now that we are staying within the system a little more, we can at least pin it back to a single blown assignment, as opposed to, "player X did this, which meant player Y got caught in a situation where they had to do this, and that left player Z on the opposite side of the ice..."
It's a trickle-down effect, but I think that the goalies playing better are b/c the team is sticking together defensively, in addition to providing a solid PK. I can't say whether or not I am making a true statement here, but when the PK is bad, it has an effect on goalies, b/c they put so much internal pressure on themselves to be that rock during 5-on-5. With our PK performing the way that it is, the goalies can ratchet up their focus on the PK even more, and 5-on-5 pressure becomes far lower to deal with.